Iron Brigade (which is the updated version of Trenched, renamed and revamped for sale overseas) is now available worldwide on Xbox Live Arcade. The game is available for 1200 Microsoft Points (about $15). Double Fine is also selling an official release day I-shirt (not a T-shirt, they say -- "that would get us sued") for $20 on its website.
Anyone who already owns Trenched will find an update when they log into the game, changing the name and adding new items, leaderboards on which to compete, and a new survival mode. We loved Trenched back when it released in June, and we're sure that by spending a little sit-down time with Iron Brigade, we can probably learn to love it too.